Salicylamide derivatives as nicotinic alpha 7 modulators

ABSTRACT

The application discloses compounds of Formula I: 
     
       
         
         
             
             
         
       
     
     wherein Q 1 , Q 2 , R 1 , R 2 , R 3 , and n are defined as described herein. Also provided are pharmaceutical compositions, methods of using, and methods of preparing the subject compounds.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is entitled to the benefit of U.S. provisional patent application Ser. No. 61/088,108 filed on Aug. 12, 2008, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to nicotinic acetylcholine receptors (nAChR), and particularly to positive allosteric modulators for the alpha 7 nAChR subtype, and methods of making and using such compounds.

BACKGROUND OF THE INVENTION

Nicotinic acetylcholine receptors (nAChR) are members of the ligand-gated ion channel family. When activated, the conductance of ions across the nicotinic ion channels increases. Nicotinic alpha 7 receptor (alpha 7 nAChR) forms a homopentameric channel in vitro that is highly permeable to calcium cations. Each alpha 7 nAChR has four transmembrane domains, known as M1, M2, M3, and M4. The M2 domain has been suggested to form the wall lining the channel. Sequence alignment shows that the alpha 7 nAChR is highly conserved during evolution. The M2 domain that lines the channel is identical in protein sequence from chick to human. Alpha 7 nAChR is described by, Revah et al. (1991), Nature, 353, 846-849; Galzi et al. (1992), Nature 359, 500-505; Fucile et al. (2000), PNAS 97(7), 3643-3648; Briggs et al. (1999), Eur. J Pharmacol. 366 (2-3), 301-308; and Gopalakrishnan et al. (1995), Eur. J Pharmacol. 290(3), 237-246.

The alpha 7 nAChR channel is expressed in various brain regions and is believed to be involved in many important biological processes in the central nervous system (CNS), including learning, memory and attention (Levin et al., Psychopharmacology (1998), 138, 217-230). Alpha 7 nAChR are localized on both presynaptic and postsynaptic terminals and have been suggested to be involved in modulating synaptic transmission. Agonists of alpha 7 nAChR have been shown to improve attention and cognition in Alzheimer's and attention deficit disorder conditions (Wilens et al., Am. J Psychiatry (1999), 156(12), 1931-1937).

The analgesic effects of nicotine have long been known. Agonists of the alpha 7 nAChR receptor have been shown to modulate production of pro-inflammatory cytokines, including interleukins (ILs), tumor necrosis factor (TNF) alpha, and high-mobility group box (HMGB-1), and to inhibit inflammatory signalling in the CNS (de Jonge et al., Br. J Pharmacol. (2007), 1-15). The alpha 7 nAChR receptor has a role in modulating CNS pain transmission, and alpha 7 nAChR agonists have shown an antinociceptive effect in an acute pain model (Damaj et al., Neuropharmacol. (2000) 39, 2785-2791.

Since acetylcholine (ACh) is an endogenous agonist of alpha 7 nAChR, agonists that act at the same site as ACh can stimulate and possibly block receptor activity through desensitization and competitive blockade processes (Forman et al., Biophysical J. (1988), 54(1), 149-158) and lead to prolonged receptor inactivation (Buisson et al., J. Neurosci. (2001), 21(6), 1819-1829). Desensitization limits the duration that the ion channel remains activated during agonist application. Thus the enhancement of Alpha 7 nAChR activity provided by such agonists will also increase competition with ACh, and therefore limit the usefulness of agonists as drugs.

Positive allosteric modulators of the nicotinic alpha 7 receptor channel enhance the activity of ACh and other nicotinic alpha 7 receptor agonists. Positive allosteric modulators activate alpha 7 nAChR when sufficient ACh is present in the central nervous system. Positive allosteric modulators of alpha 7 nAChRs thus are useful for treatment of CNS, pain and inflammatory diseases or conditions, to regulate CNS functions such as cognition, learning, mood, emotion and attention, and control production of pro-inflammatory cytokines associated with pain and inflammatory conditions. There is accordingly a need for new positive allosteric modulators of the the nicotinic alpha 7 receptor channel.

SUMMARY OF THE INVENTION

The application provides a compound of Formula I:

wherein:

-   -   Q¹ is [CH₂]_(q);     -   q is 0, 1, or 2;     -   Q² is [CH₂]_(r);         -   r is 1 or 2;     -   R¹ is R^(1′)or R^(1″);         -   R^(1′) is phenyl optionally substituted with halogen;         -   R^(1″) is cycloalkyl optionally substituted with alkynyl;     -   R² is R^(2′) or R^(2″);         -   R^(2′) is phenyl optionally substituted with lower alkoxy;         -   R^(2″) is cycloalkyl;     -   R³ is lower alkoxy or lower alkyl; and         -   n is 0, 1, or 2.

In one embodiment of Formula I, Q¹ is methylene.

In one embodiment of Formula I, R¹ is R^(1″).

In one embodiment of Formula I, Q¹ is methylene and R¹ is R^(1″).

In one embodiment of Formula I, R^(1″) is cyclopropyl.

In one embodiment of Formula I, R^(1″) is cyclopropyl and Q¹ is methylene.

In one embodiment of Formula I, Q² is methylene.

In one embodiment of Formula I, R² is phenyl.

In one embodiment of Formula I, R² is phenyl and Q² is methylene.

In one embodiment of Formula I, R² is 4-methoxy-phenyl.

In one embodiment of Formula I, q is 0.

In one embodiment of Formula I, R¹ is cyclopentyl.

In one embodiment of Formula I, q is 0 and R¹ is cyclopentyl.

In one embodiment of Formula I, Q² is ethylene.

In one embodiment of Formula I, R² is phenyl.

In one embodiment of Formula I, R² is phenyl and Q² is ethylene.

In one embodiment of Formula I, n is 2.

In one embodiment of Formula I, each R³ is independently methyl or methoxy.

In one embodiment of Formula I, n is 2 and each R³ is independently methyl or methoxy.

In one embodiment of Formula I, Q¹ is ethylene.

In one embodiment of Formula I, R¹ is R^(1′).

In one embodiment of Formula I, Q¹ is ethylene and R¹ is R^(1′).

In one embodiment of Formula I, R^(1′) is 2-fluoro-phenyl.

In one embodiment of Formula I, Q¹ is ethylene and R^(1′) is 2-fluoro-phenyl.

In one embodiment of Formula I, Q² is methylene.

In one embodiment of Formula I, R² is R^(2′).

In one embodiment of Formula I, Q² is methylene and R² is R^(2′).

In one embodiment of Formula I, R² is R^(2″).

In one embodiment of Formula I, Q² is methylene and R² is R^(2″).

In one embodiment of Formula I, n is 1.

In one embodiment of Formula I, R³ is methoxy.

In one embodiment of Formula I, n is 1 and R³ is methoxy.

In one embodiment of Formula I, n is 2.

In one embodiment of Formula I, each R³ is independently methyl or methoxy.

In one embodiment of Formula I, n is 2 and each R³ is independently methyl or methoxy.

In one embodiment of Formula I, R² is R^(2″), n is 2, and each R³ is independently methyl or methoxy.

In one embodiment of Formula I, Q² is methylene, n is 2 and each R³ is independently methyl or methoxy.

In one embodiment of Formula I, R² is R^(2″), Q² is methylene, n is 2 and each R³ is independently methyl or methoxy.

In one embodiment of Formula I, q is 0.

In one embodiment of Formula I, R¹ is R^(1″).

In one embodiment of Formula I, q is 0 and R¹ is R^(1″).

In one embodiment of Formula I, R^(1″) is 1-ethynl-cyclohexyl.

In one embodiment of Formula I, q is 0 and R^(″) is 1-ethynl-cyclohexyl.

In one embodiment of Formula I, Q² is methylene.

In one embodiment of Formula I, R² is cyclopropyl.

In one embodiment of Formula I, Q² is methylene and R² is cyclopropyl.

In one embodiment of Formula I, R² is cyclopropyl, n is 2, and each R³ is independently methyl or methoxy.

In one embodiment of Formula I, Q² is methylene, R² is cyclopropyl, n is 2, and each R³ is independently methyl or methoxy.

In one embodiment of Formula I, Q¹ is methylene and R¹ is cyclopropyl.

In one embodiment of Formula I, Q² is methylene and R² is phenyl.

In one embodiment of Formula I, Q¹ is methylene, R¹ is cyclopropyl, Q² is methylene and R² is phenyl.

In one embodiment of Formula I, Q²is methylene and R² is 4-methoxy-phenyl.

In one embodiment of Formula I, Q¹ is methylene, R¹ is cyclopropyl, Q² is methylene and R² is 4-methoxy-phenyl.

In one embodiment of Formula I, q is 0 and R¹ is cyclopentyl.

In one embodiment of Formula I, Q² is ethylene and R² is phenyl.

In one embodiment of Formula I, q is 0, R¹ is cyclopentyl, Q² is ethylene and R² is phenyl.

In one embodiment of Formula I, q is 0, R¹ is cyclopentyl, Q² is ethylene, R² is phenyl, n is 2 and each R³ is independently methyl or methoxy.

In one embodiment of Formula I, Q¹ is ethylene and R¹ is 2-fluoro-phenyl.

In one embodiment of Formula I, Q¹ is ethylene, R¹ is 2-fluoro-phenyl, Q² is methylene, and R² is R^(2′).

In one embodiment of Formula I, Q¹ is ethylene, R¹ is 2-fluoro-phenyl, Q² is methylene, R² is R^(2′), n is 1 and R³ is methoxy.

In one embodiment of Formula I, Q¹ is ethylene, R¹ is 2-fluoro-phenyl, Q² is methylene, R² is R^(2′), n is 2, and each R³ is independently methyl or methoxy.

In one embodiment of Formula I, q is 0 and R¹ is R^(1″).

In one embodiment of Formula I, R¹ is 1-ethynl-cyclohexyl, Q² is methylene and R² is cyclopropyl, q is 0.

In one embodiment of Formula I, R¹ is 1-ethynl-cyclohexyl, Q² is methylene, R² is cyclopropyl, q is 0, n is 2, and each R³ is independently methyl or methoxy.

The application also provides a compound of Formula I selected from the group consisting of:

-   4-Benzyloxy-2′-methoxy-biphenyl-3-carboxylic acid     cyclopropylmethyl-amide; -   4-Benzyloxy-2′-methoxy-biphenyl-3-carboxylic acid     [2-(2-fluoro-phenyl)-ethyl]-amide; -   4′-Methoxy-2′-methyl-4-phenethyloxy-biphenyl-3-carboxylic acid     cyclopentylamide; -   4′-Methoxy-2′-methyl-4-phenethyloxy-biphenyl-3-carboxylic acid     [2-(2-fluoro-phenyl)-ethyl]-amide; -   4′-Methoxy-4-(4-methoxy-benzyloxy)-2′-methyl-biphenyl-3-carboxylic     acid cyclopropylmethyl-amide; -   4-Cyclopropylmethoxy-4′-methoxy-2′-methyl-biphenyl-3-carboxylic acid     (1-ethynyl-cyclohexyl)-amide; and -   4-Cyclopropylmethoxy-4′-methoxy-2′-methyl-biphenyl-3-carboxylic acid     [2-(2-fluoro-phenyl)-ethyl]-amide.

The application also provides a method of enhancing cognition in a subject in need thereof, said method comprising administering to said subject an effective amount of a compound of Formula I.

The application also provides the above method, wherein said subject has Alzheimer's disease.

The application also provides a pharmaceutical composition comprising a compound of Formula I in admixture with at least one pharmaceutically acceptable carrier, diluent or excipient.

DETAILED DESCRIPTION OF THE INVENTION

The application provides compounds of Formula I:

wherein Q¹, Q², R¹, R², R³, and n are defined as described herein. Also provided are pharmaceutical compositions, methods of using, and methods of preparing the subject compounds.

Definitions

Unless otherwise stated, the following terms used in this Application, including the specification and claims, have the definitions given below. It must be noted that, as used in the specification and the appended claims, the singular forms “a”, “an,” and “the” include plural referents unless the context clearly dictates otherwise.

“Agonist” refers to a compound that enhances the activity of another compound or receptor site.

“Alkyl” means the monovalent linear or branched saturated hydrocarbon moiety, consisting solely of carbon and hydrogen atoms, having from one to twelve carbon atoms. “Lower alkyl” refers to an alkyl group of one to six carbon atoms, i.e. C₁-C₆alkyl. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, isobutyl, sec-butyl, tert-butyl, pentyl, n-hexyl, octyl, dodecyl, and the like. “Branched alkyl” means isopropyl, isobutyl, tert-butyl,

“Alkylene” or “alkylenyl” means a linear saturated divalent hydrocarbon radical of one to six carbon atoms or a branched saturated divalent hydrocarbon radical of three to six carbon atoms, e.g., methylene, ethylene, 2,2-dimethylethylene, propylene, 2-methylpropylene, butylene, pentylene, and the like.

“Alkoxy” means a moiety of the formula —OR, wherein R is an alkyl moiety as defined herein. Examples of alkoxy moieties include, but are not limited to, methoxy, ethoxy, isopropoxy, tert-butoxy and the like.

“Amino” means a moiety of the formula —NRR′ where R and R′ each independently is hydrogen or alkyl as defined herein.

“Antagonist” refers to a compound that diminishes or prevents the action of another compound or receptor site.

“Aryl” means a monovalent cyclic aromatic hydrocarbon moiety consisting of a mono-, bi- or tricyclic aromatic ring. The aryl group can be optionally substituted as defined herein. Examples of aryl moieties include, but are not limited to, phenyl, naphthyl, phenanthryl, fluorenyl, indenyl, pentalenyl, azulenyl, oxydiphenyl, biphenyl, methylenediphenyl, aminodiphenyl, diphenylsulfidyl, diphenylsulfonyl, diphenylisopropylidenyl, benzodioxanyl, benzofuranyl, benzodioxylyl, benzopyranyl, benzoxazinyl, benzoxazinonyl, benzopiperadinyl, benzopiperazinyl, benzopyrrolidinyl, benzomorpholinyl, methylenedioxyphenyl, ethylenedioxyphenyl, and the like, including partially hydrogenated derivatives thereof, each of which may be optionally substituted. Preferred aryl included optionally substituted phenyl and optionally substituted naphthyl. A preferred aryl is optionally substituted phenyl.

“Arylalkyl” and “Aralkyl”, which may be used interchangeably, mean a radical-R^(a)R^(b) where R^(a) is an alkylene group and R^(b) is an aryl group as defined herein; e.g., phenylalkyls such as benzyl, phenylethyl, 3-(3-chlorophenyl)-2-methylpentyl, and the like are examples of arylalkyl.

“Cycloalkyl” means a monovalent saturated carbocyclic moiety consisting of mono- or bicyclic rings. Cycloalkyl can optionally be substituted with one or more substituents, wherein each substituent is independently hydroxy, alkyl, alkoxy, halo, haloalkyl, amino, monoalkylamino, or dialkylamino, unless otherwise specifically indicated. Examples of cycloalkyl moieties include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and the like, including partially unsaturated derivatives thereof.

“Cycloalkylalkyl” means a moiety of the formula —R′—R″, where R′ is alkylene and R″ is cycloalkyl as defined herein.

“Heteroalkyl” means an alkyl radical as defined herein, including a branched C₄-C₇-alkyl, wherein one, two or three hydrogen atoms have been replaced with a substituent independently selected from the group consisting of —OR^(a), —NR^(b)R^(c), and —S(O)_(n)R^(d) (where n is an integer from 0 to 2), with the understanding that the point of attachment of the heteroalkyl radical is through a carbon atom, wherein R^(a) is hydrogen, acyl, alkyl, cycloalkyl, or cycloalkylalkyl; R^(b) and R^(c) are independently of each other hydrogen, acyl, alkyl, cycloalkyl, or cycloalkylalkyl; and when n is 0, R^(d) is hydrogen, alkyl, cycloalkyl, or cycloalkylalkyl, and when n is 1 or 2, R^(d) is alkyl, cycloalkyl, cycloalkylalkyl, amino, acylamino, monoalkylamino, or dialkylamino. Representative examples include, but are not limited to, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxy-1-hydroxymethylethyl, 2,3-dihydroxypropyl, 1-hydroxymethylethyl, 3-hydroxybutyl, 2,3-dihydroxybutyl, 2-hydroxy-1-methylpropyl, 2-aminoethyl, 3-aminopropyl, 2-methylsulfonylethyl, aminosulfonylmethyl, aminosulfonylethyl, aminosulfonylpropyl, methylaminosulfonylmethyl, methylaminosulfonylethyl, methylaminosulfonylpropyl, and the like.

“Heteroaryl” means a monocyclic, bicyclic or tricyclic radical of 5 to 12 ring atoms having at least one aromatic ring containing one, two, or three ring heteroatoms selected from N, O, or S, the remaining ring atoms being C, with the understanding that the attachment point of the heteroaryl radical will be on an aromatic ring. The heteroaryl ring may be optionally substituted as defined herein. Examples of heteroaryl moieties include, but are not limited to, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, oxadiazolyl, thiadiazolyl, pyrazinyl, thienyl, thiophenyl, furanyl, pyranyl, pyridinyl, pyrrolyl, pyrazolyl, pyrimidyl, quinolinyl, isoquinolinyl, benzofuryl, benzofuranyl, benzothiophenyl, benzothiopyranyl, benzimidazolyl, benzoxazolyl, benzooxadiazolyl, benzothiazolyl, benzothiadiazolyl, benzopyranyl, indolyl, isoindolyl, triazolyl, triazinyl, quinoxalinyl, purinyl, quinazolinyl, quinolizinyl, naphthyridinyl, pteridinyl, carbazolyl, azepinyl, diazepinyl, acridinyl and the like, including partially hydrogenated derivatives thereof, each of which may be optionally substituted. Preferred heteroaryl include indolyl, pyridinyl, pyrimidinyl, thienyl, furanyl pyrrolyl, imidazolyl and pyrazolyl, each of which may be optionally substituted.

“Heteroarylalkyl” and “heteroaralkyl”, which may be used interchangeably, mean a radical-R^(a)R^(b) where R^(a) is an alkylene group and R^(b) is a heteroaryl group as defined herein

The terms “halo” and “halogen”, which may be used interchangeably, refer to a substituent fluoro, chloro, bromo, or iodo.

“Haloalkyl” means alkyl as defined herein in which one or more hydrogen has been replaced with same or different halogen. Exemplary haloalkyls include —CH₂Cl, —CH₂CF₃, —CH₂CCl₃, perfluoroalkyl (e.g., —CF₃), and the like.

“Heterocyclyl” or “heterocycloalkyl” means a monovalent saturated moiety, consisting of one to three rings, incorporating one, two, or three or four heteroatoms (chosen from nitrogen, oxygen or sulfur). The heterocyclyl ring may be optionally substituted as defined herein. Examples of heterocyclyl moieties include, but are not limited to, optionally substituted piperidinyl, piperazinyl, homopiperazinyl, azepinyl, pyrrolidinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, pyridinyl, pyridazinyl, pyrimidinyl, oxazolidinyl, isoxazolidinyl, morpholinyl, thiazolidinyl, isothiazolidinyl, quinuclidinyl, quinolinyl, isoquinolinyl, benzimidazolyl, thiadiazolylidinyl, benzothiazolidinyl, benzoazolylidinyl, dihydrofuryl, tetrahydrofuryl, dihydropyranyl, tetrahydropyranyl, thiamorpholinyl, thiamorpholinylsulfoxide, thiamorpholinylsulfone, dihydroquinolinyl, dihydrisoquinolinyl, tetrahydroquinolinyl, tetrahydrisoquinolinyl, and the like.

“Optionally substituted”, when used in association with “aryl”, phenyl”, “heteroaryl” (including indolyl such as indol-1-yl, indol-2-yl and indol-3-yl, 2,3-dihydroindolyl such as 2,3-dihydroindol-1-yl, 2,3-dihydroindol-2-yl and 2,3-dihydroindol-3-yl, indazolyl such as indazol-1-yl, indazol-2-yl and indazol-3-yl, benzimidazolyl such as benzimidazol-1-yl and benzimidazol-2-yl, benzofuranyl such as benzofuran-2-yl and benzofuran-3-yl, benzothiophenyl such as benzothiophen-2-yl and benzothiophen-3-yl, benzoxazol-2-yl, benzothiazol-2-yl, thienyl, furanyl, pyridinyl, pyrimidinyl, pyridazinyl, pyrazinyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, imidazolyl, pyrazolyl and quinolinyl)” or “heterocyclyl”, means an aryl, phenyl, heteroaryl or heterocyclyl which is optionally substituted independently with one to four substituents, preferably one or two substituents selected from alkyl, cycloalkyl, alkoxy, halo, haloalkyl, haloalkoxy, cyano, nitro, heteroalkyl, amino, mono-alkylamino, di-alkylamino, hydroxyalkyl, alkoxyalkyl, alkylsulfonyl, alkylsulfonamido, benzyloxy, cycloalkylalkyl, cycloalkoxy, cycloalkylalkoxy, alkylsulfonyloxy, optionally substituted thienyl, optionally substituted pyrazolyl, optionally substituted pyridinyl, morpholinocarbonyl, —CH₂)_(q)—S(O)_(r)R^(f); —(CH₂)_(q)—NR^(g)R^(h); —(CH₂)_(q)—C(═O)—NR^(g)R^(h); —(CH₂)_(q)—(═O)—C(═O)—NR^(g)R^(h); —(CH₂)_(q)—SO₂—NR^(g)R^(h); —(CH₂)_(q)—N(R^(f))—C(═O)—R^(i); —(CH₂)_(q)—C(═O)—R^(i); or —(CH₂)_(q)—N(R^(f))—SO₂—R^(g); where q is 0 or 1, r is from 0 to 2, R^(f), R^(g), and R^(h) each independently is hydrogen or alkyl, and each R^(i) is independently hydrogen, alkyl, hydroxy, or alkoxy. Certain preferred optional substituents for “aryl”, phenyl”, “heteroaryl” “cycloalkyl” or “heterocyclyl” include alkyl, halo, haloalkyl, alkoxy, cyano, amino, aminosulfonyl, and alkylsulfonyl. More preferred substituents are methyl, fluoro, chloro, trifluoromethyl, methoxy, amino, aminosulfonyl and methanesulfonyl.

“Leaving group” means the group with the meaning conventionally associated with it in synthetic organic chemistry, i.e., an atom or group displaceable under substitution reaction conditions. Examples of leaving groups include, but are not limited to, halogen, alkane- or arylenesulfonyloxy, such as methanesulfonyloxy, ethanesulfonyloxy, thiomethyl, benzenesulfonyloxy, tosyloxy, and thienyloxy, dihalophosphinoyloxy, optionally substituted benzyloxy, isopropyloxy, acyloxy, and the like.

“Modulator” means a molecule that interacts with a target. The interactions include, but are not limited to, agonist, antagonist, and the like, as defined herein.

“Optional” or “optionally” means that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances in which it does not.

“Disease” and “Disease state” means any disease, condition, symptom, disorder or indication.

“Inert organic solvent” or “inert solvent” means the solvent is inert under the conditions of the reaction being described in conjunction therewith, including for example, benzene, toluene, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, chloroform, methylene chloride or dichloromethane, dichloroethane, diethyl ether, ethyl acetate, acetone, methyl ethyl ketone, methanol, ethanol, propanol, isopropanol, tert-butanol, dioxane, pyridine, and the like. Unless specified to the contrary, the solvents used in the reactions of the present invention are inert solvents.

“Pharmaceutically acceptable” means that which is useful in preparing a pharmaceutical composition that is generally safe, non-toxic, and neither biologically nor otherwise undesirable and includes that which is acceptable for veterinary as well as human pharmaceutical use.

“Pharmaceutically acceptable salts” of a compound means salts that are pharmaceutically acceptable, as defined herein, and that possess the desired pharmacological activity of the parent compound. Such salts include:

Acid addition salts formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids such as acetic acid, benzenesulfonic acid, benzoic, camphorsulfonic acid, citric acid, ethanesulfonic acid, fumaric acid, glucoheptonic acid, gluconic acid, glutamic acid, glycolic acid, hydroxynaphtoic acid, 2-hydroxyethanesulfonic acid, lactic acid, maleic acid, malic acid, malonic acid, mandelic acid, methanesulfonic acid, muconic acid, 2-naphthalenesulfonic acid, propionic acid, salicylic acid, succinic acid, tartaric acid, p-toluenesulfonic acid, trimethylacetic acid, and the like; or salts formed when an acidic proton present in the parent compound either is replaced by a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic or inorganic base. Acceptable organic bases include diethanolamine, ethanolamine, N-methylglucamine, triethanolamine, tromethamine, and the like. Acceptable inorganic bases include aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate and sodium hydroxide.

The preferred pharmaceutically acceptable salts are the salts formed from acetic acid, hydrochloric acid, sulphuric acid, methanesulfonic acid, maleic acid, phosphoric acid, tartaric acid, citric acid, sodium, potassium, calcium, zinc, and magnesium.

It should be understood that all references to pharmaceutically acceptable salts include solvent addition forms (solvates) or crystal forms (polymorphs) as defined herein, of the same acid addition salt.

“Protective group” or “protecting group” means the group which selectively blocks one reactive site in a multifunctional compound such that a chemical reaction can be carried out selectively at another unprotected reactive site in the meaning conventionally associated with it in synthetic chemistry. Certain processes of this invention rely upon the protective groups to block reactive nitrogen and/or oxygen atoms present in the reactants. For example, the terms “amino-protecting group” and “nitrogen protecting group” are used interchangeably herein and refer to those organic groups intended to protect the nitrogen atom against undesirable reactions during synthetic procedures. Exemplary nitrogen protecting groups include, but are not limited to, trifluoroacetyl, acetamido, benzyl (Bn), benzyloxycarbonyl (carbobenzyloxy, CBZ), p-methoxybenzyloxycarbonyl, p-nitrobenzyloxycarbonyl, tert-butoxycarbonyl (BOC), and the like. Skilled persons will know how to choose a group for the ease of removal and for the ability to withstand the following reactions.

“Solvates” means solvent additions forms that contain either stoichiometric or non stoichiometric amounts of solvent. Some compounds have a tendency to trap a fixed molar ratio of solvent molecules in the crystalline solid state, thus forming a solvate. If the solvent is water the solvate formed is a hydrate, when the solvent is alcohol, the solvate formed is an alcoholate. Hydrates are formed by the combination of one or more molecules of water with one of the substances in which the water retains its molecular state as H₂O, such combination being able to form one or more hydrate.

“Subject” means mammals and non-mammals. Mammals means any member of the mammalia class including, but not limited to, humans; non-human primates such as chimpanzees and other apes and monkey species; farm animals such as cattle, horses, sheep, goats, and swine; domestic animals such as rabbits, dogs, and cats; laboratory animals including rodents, such as rats, mice, and guinea pigs; and the like. Examples of non-mammals include, but are not limited to, birds, and the like. The term “subject” does not denote a particular age or sex.

“Pain” and pain conditions (states) as used herein means pain associated with any of a wide variety of causes, including but not limited to, inflammatory pain, surgical pain, visceral pain, dental pain, premenstrual pain, central pain, pain due to burns, migraine or cluster headaches, nerve injury, neuritis, neuralgias, poisoning, ischemic injury, interstitial cystitis, cancer pain, viral, parasitic or bacterial infection, post-traumatic injuries (including fractures and sports injuries), and pain associated with functional bowel disorders such as irritable bowel syndrome.

“Inflammation” means any pathological process characterized by injury or destruction of tissues resulting from cytologic reactions, chemical reactions or other causes. Inflammation may be manifested by signs of pain, heat, redness, swelling, and loss of function. Inflammation indications include, but are not limited to, bacterial, fungal or viral infections, rheumatoid arthritis, osteoarthritis, surgery, bladder infection or idiopathic bladder inflammation, over-use, old age, or nutritional deficiencies, prostatis and conjunctivitis.

“Cognition” means any mental process associated with acquiring and retaining knowledge. A “cognition disorder” means any disturbance to the mental process or processes related to thinking, reasoning, judgment ad memory. Cognition disorders may result from or other wise be associated with Parkinson's disease, Huntington's disease, anxiety, depression, manic depression, psychosis, epilepsy, obsessive compulsive disorders, mood disorders, migraine, Alzheimer's disease, sleep disorders, feeding disorders such as anorexia, bulimia, and obesity, panic attacks, akathisia, attention deficit hyperactivity disorder (ADHD), attention deficit disorder (ADD), withdrawal from drug abuse such as cocaine, ethanol, nicotine and benzodiazepines, schizophrenia, and also disorders associated with spinal trauma and/or head injury such as hydrocephalus.

“Therapeutically effective amount” means an amount of a compound that, when administered to a subject for treating a disease state, is sufficient to effect such treatment for the disease state. The “therapeutically effective amount” will vary depending on the compound, disease state being treated, the severity or the disease treated, the age and relative health of the subject, the route and form of administration, the judgment of the attending medical or veterinary practitioner, and other factors.

The terms “those defined above” and “those defined herein” when referring to a variable incorporates by reference the broad definition of the variable as well as preferred, more preferred and most preferred definitions, if any.

“Treating” or “treatment” of a disease state includes:

-   -   (i) preventing the disease state, i.e. causing the clinical         symptoms of the disease state not to develop in a subject that         may be exposed to or predisposed to the disease state, but does         not yet experience or display symptoms of the disease state.     -   (ii) inhibiting the disease state, i.e., arresting the         development of the disease state or its clinical symptoms, or     -   (iii) relieving the disease state, i.e., causing temporary or         permanent regression of the disease state or its clinical         symptoms.

The terms “treating”, “contacting” and “reacting” when referring to a chemical reaction means adding or mixing two or more reagents under appropriate conditions to produce the indicated and/or the desired product. It should be appreciated that the reaction which produces the indicated and/or the desired product may not necessarily result directly from the combination of two reagents which were initially added, i.e., there may be one or more intermediates which are produced in the mixture which ultimately leads to the formation of the indicated and/or the desired product.

Nomenclature and Structures

In general, the nomenclature used in this Application is based on AUTONOM™ v.4.0, a Beilstein Institute computerized system for the generation of IUPAC systematic nomenclature. Chemical structures shown herein were prepared using ISIS® version 2.2. Any open valency appearing on a carbon, oxygen, sulfur or nitrogen atom in the structures herein indicates the presence of a hydrogen atom.

Whenever a chiral carbon is present in a chemical structure, it is intended that all stereoisomers associated with that chiral carbon are encompassed by the structure.

All patents and publications identified herein are incorporated herein by reference in their entirety.

Representative compounds in accordance with the methods of the invention are shown in Table 1.

TABLE 1 # Structure Name I-1

4-Benzyloxy-2′-methoxy- biphenyl-3-carboxylic acid cyclopropylmethyl-amide I-2

4-Benzyloxy-2′-methoxy- biphenyl-3-carboxylic acid [2-(2-fluoro-phenyl)-ethyl]- amide I-3

4′-Methoxy-2′-methyl-4- phenethyloxy-biphenyl-3- carboxylic acid cyclopentylamide I-4

4′-Methoxy-2′-methyl-4- phenethyloxy-biphenyl-3- carboxylic acid [2-(2-fluoro- phenyl)-ethyl]-amide I-5

4′-Methoxy-4-(4-methoxy- benzyloxy)-2′-methyl- biphenyl-3-carboxylic acid cyclopropylmethyl-amide I-6

4-Cyclopropylmethoxy-4′- methoxy-2′-methyl-biphenyl- 3-carboxylic acid (1-ethynyl- cyclohexyl)-amide I-7

4-Cyclopropylmethoxy-4′- methoxy-2′-methyl-biphenyl- 3-carboxylic acid [2-(2- fluoro-phenyl)-ethyl]-amide

Synthesis

Compounds of the present invention can be made by a variety of methods depicted in the illustrative synthetic reaction schemes shown and described below.

The starting materials and reagents used in preparing these compounds generally are either available from commercial suppliers, such as Aldrich Chemical Co., or are prepared by methods known to those skilled in the art following procedures set forth in references such as Fieser and Fieser's Reagents for Organic Synthesis; Wiley & Sons: New York, 1991, Volumes 1-15; Rodd's Chemistry of Carbon Compounds, Elsevier Science Publishers, 1989, Volumes 1-5 and Supplementals; and Organic Reactions, Wiley & Sons: New York, 1991, Volumes 1-40. The following synthetic reaction schemes are merely illustrative of some methods by which the compounds of the present invention can be synthesized, and various modifications to these synthetic reaction schemes can be made and will be suggested to one skilled in the art having referred to the disclosure contained in this Application.

The starting materials and the intermediates of the synthetic reaction schemes can be isolated and purified if desired using conventional techniques, including but not limited to, filtration, distillation, crystallization, chromatography, and the like. Such materials can be characterized using conventional means, including physical constants and spectral data.

Unless specified to the contrary, the reactions described herein preferably are conducted under an inert atmosphere at atmospheric pressure at a reaction temperature range of from about −78° C. to about 150° C., more preferably from about 0° C. to about 125° C., and most preferably and conveniently at about room (or ambient) temperature, e.g., about 20° C.

Utility

The compounds of the invention are usable for the treatment of diseases or conditions associated with the nicotinic alpha 7 (α7nACh) receptor, including treatment of psychotic diseases, neurodegenerative diseases, and cognitive impairments involving a dysfunction of the cholinergic system, and conditions of memory and/or cognition impairment, including, for example, schizophrenia, anxiety, mania, depression, manic depression, Tourette's syndrome, Parkinson's disease, Huntington's disease, cognitive disorders (such as Alzheimer's disease, Lewy Body Dementia, Amyotrophic Lateral Sclerosis, memory impairment, memory loss, cognition deficit, attention deficit, Attention Deficit Hyperactivity Disorder), and other uses such as treatment of nicotine addiction, inducing smoking cessation, treating pain (i.e., analgesic use), providing neuroprotection, and treating jetlag. The compounds of the invention are useful for enhancing cognition in Alzheimer's patients and patients having cognition impairment or cognitive disorders associated with schizophrenia, anxiety, mania, depression, manic depression, Tourette's syndrome, Parkinson's disease, Huntington's disease, Lewy Body Dementia, Amyotrophic Lateral Sclerosis, memory impairment, memory loss, cognition deficit, attention deficit or Attention Deficit Hyperactivity Disorder.

Thus, the invention provides a method of treating a patient or subject, specifically a mammal and especially a human, suffering from psychotic diseases, neurodegenerative diseases involving a dysfunction of the cholinergic system, and conditions of memory and/or cognition impairment, including, for example, schizophrenia, anxiety, mania, depression, manic depression [examples of psychotic disorders], Tourette's syndrome, Parkinson's disease, Huntington's disease [examples of neurodegenerative diseases], and/or cognitive disorders (such as Alzheimer's disease, Lewy Body Dementia, Amyotrophic Lateral Sclerosis, memory impairment, memory loss, cognition deficit, attention deficit, Attention Deficit Hyperactivity Disorder) comprising administering to the patient an effective amount of a compound of the invention.

Neurodegenerative disorders include, but are not limited to, treatment and/or prophylaxis of Alzheimer's diseases, Pick's disease, diffuse Lewy Body disease, progressive supranuclear palsy (Steel-Richardson syndrome), multisystem degeneration (Shy-Drager syndrome), motor neuron diseases including amyotrophic lateral sclerosis, degenerative ataxias, cortical basal degeneration, ALS-Parkinson's-Dementia complex of Guam, subacute sclerosing panencephalitis, Huntington's disease, Parkinson's disease, synucleinopathies, primary progressive aphasia, striatonigral degeneration, Machado-Joseph disease/spinocerebellar ataxia type 3, olivopontocerebellar degenerations, Gilles De La Tourette's disease, bulbar, pseudobulbar palsy, spinal muscular atrophy, spinobulbar muscular atrophy (Kennedy's disease), primary lateral sclerosis, familial spastic paraplegia, Werdnig-Hoffmann disease, Kugelberg-Welander disease, Tay-Sach's disease, Sandhoff disease, familial spastic disease, Wohlfart-Kugelberg-Welander disease, spastic paraparesis, progressive multifocal leukoencephalopathy, prion diseases (such as Creutzfeldt-Jakob, Gerstmann-Sträussler-Scheinker disease, Kuru and fatal familial insomnia), and neurodegenerative disorders resulting from cerebral ischemia or infarction including embolic occlusion and thrombotic occlusion as well as intracranial hemorrhage of any type (including, but not limited to, epidural, subdural, subarachnoid and intracerebral), and intracranial and intravertebral lesions (including, but not limited to, contusion, penetration, shear, compression and laceration).

In addition, the compounds of the invention may be used to treat age-related dementia and other dementias and conditions with memory loss including age-related memory loss, senility, vascular dementia, diffuse white matter disease (Binswanger's disease), dementia of endocrine or metabolic origin, dementia of head trauma and diffuse brain damage, dementia pugilistica and frontal lobe dementia. Thus, the invention provides a method of treating a patient, especially a human, suffering from age-related dementia and other dementias and conditions with memory loss, as well as enhancing cognitive memory in Alzheimer's patients, comprising administering to the patient an effective amount of a compound of the invention.

The invention provides methods of treating subjects suffering from memory impairment due to, for example, Alzheimer's disease, mild cognitive impairment due to aging, schizophrenia, Parkinson's disease, Huntington's disease, Pick's disease, Creutzfeldt-Jakob disease, depression, aging, head trauma, stroke, CNS hypoxia, cerebral senility, multiinfarct dementia and other neurological conditions, as well as HIV and cardiovascular diseases, comprising administering an effective amount of a compound of the invention.

Amyloid precursor protein (APP) and Aβ peptides derived therefrom, e.g., Aβ₁₋₄₀, Aβ₁₋₄₂, and other fragments, are known to be involved in the pathology of Alzheimer's disease. The Aβ₁₋₄₂ peptides are not only implicated in neurotoxicity but also are known to inhibit cholinergic transmitter function. Further, it has been determined that Aβ peptides bind to α7nACh receptors. Agents which block the binding of the AP peptides to α-7 nAChRs are thus useful for treating neurodegenerative diseases. In addition, stimulation α7nACh receptors can protect neurons against cytotoxicity associated with Aβ peptides. Thus, the invention provides a method of treating and/or preventing dementia in an Alzheimer's patient which comprises administering to the subject a therapeutically effective amount of a compound according to Formula I to inhibit the binding of an amyloid beta peptide (preferably, Aβ₁₋₄₂) with nACh receptors, preferable α7nACh receptors, most preferably, human α7nACh receptors (as well as a method for treating and/or preventing other clinical manifestations of Alzheimer's disease that include, but are not limited to, cognitive and language deficits, apraxias, depression, delusions and other neuropsychiatric symptoms and signs, and movement and gait abnormalities).

The invention also provides methods for treating other amyloidosis diseases, for example, hereditary cerebral angiopathy, nonneuropathic hereditary amyloid, Down's syndrome, macroglobulinemia, secondary familial Mediterranean fever, Muckle-Wells syndrome, multiple myeloma, pancreatic- and cardiac-related amyloidosis, chronic hemodialysis anthropathy, and Finnish and Iowa amyloidosis.

Nicotinic receptors have been implicated as playing a role in the body's response to alcohol ingestion, and the compounds of the invention are useful in the treatment of alcohol withdrawal and in anti-intoxication therapy.

Agonists for the α7nACh receptor subtypes can also be used for neuroprotection against damage associated with strokes and ischemia and glutamate-induced excitotoxicity, and the invention thus provides a method of treating a patient to provide for neuroprotection against damage associated with strokes and ischemia and glutamate-induced excitotoxicity comprising administering to the patient an effective amount of a compound of the invention.

Agonists for the α7nACh receptor subtypes can also be used in the treatment of nicotine addiction, inducing smoking cessation, treating pain, and treating jetlag, obesity, diabetes, and inflammation, and the invention thus provides a method of treating a patient suffering from nicotine addiction, pain, jetlag, obesity, diabetes, and/or inflammation, or a method of inducing smoking cessation in a patient comprising administering to the patient an effective amount of a compound of the invention

The inflammatory reflex is an autonomic nervous system response to an inflammatory signal. Upon sensing an inflammatory stimulus, the autonomic nervous system responds through the vagus nerve by releasing acetylcholine and activating nicotinic α7 receptors on macrophages. These macrophages in turn release cytokines. Dysfunctions in this pathway have been linked to human inflammatory diseases including rheumatoid arthritis, diabetes and sepsis. Macrophages express the nicotinic α7 receptor and it is likely this receptor that mediates the cholinergic anti-inflammatory response. Therefore, compounds of the invention may be useful for treating a patient (e.g., a mammal, such as a human) suffering from an inflammatory disease or disorder, such as, but not limited to, rheumatoid arthritis, diabetes or sepsis.

The compounds of the invention are expected to find utility as analgesics in the treatment of diseases and conditions associated with pain from a wide variety of causes, including, but not limited to, inflammatory pain, surgical pain, visceral pain, dental pain, premenstrual pain, central pain, pain due to burns, migraine or cluster headaches, nerve injury, neuritis, neuralgias, poisoning, ischemic injury, interstitial cystitis, cancer pain, viral, parasitic or bacterial infection, post-traumatic injuries (including fractures and sports injuries), and pain associated with functional bowel disorders such as irritable bowel syndrome.

Further, compounds of the invention are useful for treating respiratory disorders, including chronic obstructive pulmonary disorder (COPD), asthma, bronchospasm, and the like.

In addition, due to their affinity to α7nACh receptors, labeled derivatives of the compounds of Formula I (e.g., C¹¹ or F¹⁸ labeled derivatives), can be used in neuroimaging of the receptors within, e.g., the brain. Thus, using such labeled agents in vivo imaging of the receptors can be performed using, e.g., PET imaging.

The invention also provides a method of treating a patient suffering from, for example, mild cognitive impairment (MCI), vascular dementia (VaD), age-associated cognitive decline (AACD), amnesia associated w/open-heart-surgery, cardiac arrest, and/or general anesthesia, memory deficits from early exposure of anesthetic agents, sleep deprivation induced cognitive impairment, chronic fatigue syndrome, narcolepsy, AIDS-related dementia, epilepsy-related cognitive impairment, Down's syndrome, Alcoholism related dementia, drug/substance induced memory impairments, Dementia Puglistica (Boxer Syndrome), and animal dementia (e.g., dogs, cats, horses, etc.) comprising administering to the patient an effective amount of a compound of the invention.

Administration and Pharmaceutical Composition

The invention includes pharmaceutical compositions comprising at least one compound of the present invention, or an individual isomer, racemic or non-racemic mixture of isomers or a pharmaceutically acceptable salt or solvate thereof, together with at least one pharmaceutically acceptable carrier, and optionally other therapeutic and/or prophylactic ingredients. In general, the compounds of the invention will be administered in a therapeutically effective amount by any of the accepted modes of administration for agents that serve similar utilities. Suitable dosage ranges are typically 1-500 mg daily, preferably 1-100 mg daily, and most preferably 1-30 mg daily, depending upon numerous factors such as the severity of the disease to be treated, the age and relative health of the subject, the potency of the compound used, the route and form of administration, the indication towards which the administration is directed, and the preferences and experience of the medical practitioner involved. One of ordinary skill in the art of treating such diseases will be able, without undue experimentation and in reliance upon personal knowledge and the disclosure of this Application, to ascertain a therapeutically effective amount of the compounds of the present invention for a given disease.

Compounds of the invention may be administered as pharmaceutical formulations including those suitable for oral (including buccal and sub-lingual), rectal, nasal, topical, pulmonary, vaginal, or parenteral (including intramuscular, intraarterial, intrathecal, subcutaneous and intravenous) administration or in a form suitable for administration by inhalation or insufflation. The preferred manner of administration is generally oral using a convenient daily dosage regimen which can be adjusted according to the degree of affliction.

A compound or compounds of the invention, together with one or more conventional adjuvants, carriers, or diluents, may be placed into the form of pharmaceutical compositions and unit dosages. The pharmaceutical compositions and unit dosage forms may be comprised of conventional ingredients in conventional proportions, with or without additional active compounds or principles, and the unit dosage forms may contain any suitable effective amount of the active ingredient commensurate with the intended daily dosage range to be employed. The pharmaceutical compositions may be employed as solids, such as tablets or filled capsules, semisolids, powders, sustained release formulations, or liquids such as solutions, suspensions, emulsions, elixirs, or filled capsules for oral use; or in the form of suppositories for rectal or vaginal administration; or in the form of sterile injectable solutions for parenteral use. Formulations containing about one (1) milligram of active ingredient or, more broadly, about 0.01 to about one hundred (100) milligrams, per tablet, are accordingly suitable representative unit dosage forms.

The compounds of the invention may be formulated in a wide variety of oral administration dosage forms. The pharmaceutical compositions and dosage forms may comprise a compound or compounds of the present invention or pharmaceutically acceptable salts thereof as the active component. The pharmaceutically acceptable carriers may be either solid or liquid. Solid form preparations include powders, tablets, pills, capsules, cachets, suppositories, and dispersible granules. A solid carrier may be one or more substances which may also act as diluents, flavouring agents, solubilizers, lubricants, suspending agents, binders, preservatives, tablet disintegrating agents, or an encapsulating material. In powders, the carrier generally is a finely divided solid which is a mixture with the finely divided active component. In tablets, the active component generally is mixed with the carrier having the necessary binding capacity in suitable proportions and compacted in the shape and size desired. The powders and tablets preferably contain from about one (1) to about seventy (70) percent of the active compound. Suitable carriers include but are not limited to magnesium carbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin, starch, gelatine, tragacanth, methylcellulose, sodium carboxymethylcellulose, a low melting wax, cocoa butter, and the like. The term “preparation” is intended to include the formulation of the active compound with encapsulating material as carrier, providing a capsule in which the active component, with or without carriers, is surrounded by a carrier, which is in association with it. Similarly, cachets and lozenges are included. Tablets, powders, capsules, pills, cachets, and lozenges may be as solid forms suitable for oral administration.

Other forms suitable for oral administration include liquid form preparations including emulsions, syrups, elixirs, aqueous solutions, aqueous suspensions, or solid form preparations which are intended to be converted shortly before use to liquid form preparations. Emulsions may be prepared in solutions, for example, in aqueous propylene glycol solutions or may contain emulsifying agents, for example, such as lecithin, sorbitan monooleate, or acacia. Aqueous solutions can be prepared by dissolving the active component in water and adding suitable colorants, flavors, stabilizers, and thickening agents. Aqueous suspensions can be prepared by dispersing the finely divided active component in water with viscous material, such as natural or synthetic gums, resins, methylcellulose, sodium carboxymethylcellulose, and other well known suspending agents. Solid form preparations include solutions, suspensions, and emulsions, and may contain, in addition to the active component, colorants, flavors, stabilizers, buffers, artificial and natural sweeteners, dispersants, thickeners, solubilizing agents, and the like.

The compounds of the invention may be formulated for parenteral administration (e.g., by injection, for example bolus injection or continuous infusion) and may be presented in unit dose form in ampoules, pre-filled syringes, small volume infusion or in multi-dose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, for example solutions in aqueous polyethylene glycol. Examples of oily or nonaqueous carriers, diluents, solvents or vehicles include propylene glycol, polyethylene glycol, vegetable oils (e.g., olive oil), and injectable organic esters (e.g., ethyl oleate), and may contain formulatory agents such as preserving, wetting, emulsifying or suspending, stabilizing and/or dispersing agents. Alternatively, the active ingredient may be in powder form, obtained by aseptic isolation of sterile solid or by lyophilization from solution for constitution before use with a suitable vehicle, e.g., sterile, pyrogen-free water.

The compounds of the invention may be formulated for topical administration to the epidermis as ointments, creams or lotions, or as a transdermal patch. Ointments and creams may, for example, be formulated with an aqueous or oily base with the addition of suitable thickening and/or gelling agents. Lotions may be formulated with an aqueous or oily base and will in general also containing one or more emulsifying agents, stabilizing agents, dispersing agents, suspending agents, thickening agents, or coloring agents. Formulations suitable for topical administration in the mouth include lozenges comprising active agents in a flavored base, usually sucrose and acacia or tragacanth; pastilles comprising the active ingredient in an inert base such as gelatine and glycerine or sucrose and acacia; and mouthwashes comprising the active ingredient in a suitable liquid carrier.

The compounds of the invention may be formulated for administration as suppositories. A low melting wax, such as a mixture of fatty acid glycerides or cocoa butter is first melted and the active component is dispersed homogeneously, for example, by stirring. The molten homogeneous mixture is then poured into convenient sized molds, allowed to cool, and to solidify.

The compounds of the invention may be formulated for vaginal administration. Pessaries, tampons, creams, gels, pastes, foams or sprays containing in addition to the active ingredient such carriers as are known in the art to be appropriate.

The subject compounds may be formulated for nasal administration. The solutions or suspensions are applied directly to the nasal cavity by conventional means, for example, with a dropper, pipette or spray. The formulations may be provided in a single or multidose form. In the latter case of a dropper or pipette, this may be achieved by the patient administering an appropriate, predetermined volume of the solution or suspension. In the case of a spray, this may be achieved for example by means of a metering atomizing spray pump.

The compounds of the invention may be formulated for aerosol administration, particularly to the respiratory tract and including intranasal administration. The compound will generally have a small particle size for example of the order of five (5) microns or less. Such a particle size may be obtained by means known in the art, for example by micronization. The active ingredient is provided in a pressurized pack with a suitable propellant such as a chlorofluorocarbon (CFC), for example, dichlorodifluoromethane, trichlorofluoromethane, or dichlorotetrafluoroethane, or carbon dioxide or other suitable gas. The aerosol may conveniently also contain a surfactant such as lecithin. The dose of drug may be controlled by a metered valve. Alternatively the active ingredients may be provided in a form of a dry powder, for example a powder mix of the compound in a suitable powder base such as lactose, starch, starch derivatives such as hydroxypropylmethyl cellulose and polyvinylpyrrolidine (PVP). The powder carrier will form a gel in the nasal cavity. The powder composition may be presented in unit dose form for example in capsules or cartridges of e.g., gelatine or blister packs from which the powder may be administered by means of an inhaler.

When desired, formulations can be prepared with enteric coatings adapted for sustained or controlled release administration of the active ingredient. For example, the compounds of the present invention can be formulated in transdermal or subcutaneous drug delivery devices. These delivery systems are advantageous when sustained release of the compound is necessary and when patient compliance with a treatment regimen is crucial. Compounds in transdermal delivery systems are frequently attached to a skin-adhesive solid support. The compound of interest can also be combined with a penetration enhancer, e.g., Azone(1-dodecylazacycloheptan-2-one). Sustained release delivery systems are inserted subcutaneously into the subdermal layer by surgery or injection. The subdermal implants encapsulate the compound in a lipid soluble membrane, e.g., silicone rubber, or a biodegradable polymer, e.g., polylactic acid.

The pharmaceutical preparations are preferably in unit dosage forms. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage form can be a packaged preparation, the package containing discrete quantities of preparation, such as packeted tablets, capsules, and powders in vials or ampoules. Also, the unit dosage form can be a capsule, tablet, cachet, or lozenge itself, or it can be the appropriate number of any of these in packaged form.

Other suitable pharmaceutical carriers and their formulations are described in Remington: The Science and Practice of Pharmacy 1995, edited by E. W. Martin, Mack Publishing Company, 19th edition, Easton, Pa. Representative pharmaceutical formulations containing a compound of the present invention are described below.

EXAMPLES

The following preparations and examples are given to enable those skilled in the art to more clearly understand and to practice the present invention. They should not be considered as limiting the scope of the invention, but merely as being illustrative and representative thereof. The following abbreviations may be used in the Examples.

Abbreviations

CDI 1,1-carbonyl-diimidazole

DCM dichloromethane/methylene chloride

DMF N,N-dimethylformamide

DMAP 4-dimethylaminopyridine

EDCI 1-ethyl-3-(3′-dimethylaminopropyl)carbodiimide

EtOAc ethyl acetate

EtOH ethanol

tBuOH tert-butanol

gc gas chromatography

HMPA hexamethylphosphoramide

HOAc acetic acid

HOBt N-Hydroxybenzotriazole

hplc high performance liquid chromatography

mCPBA m-chloroperbenzoic acid

MeCN acetonitrile

MeOH methanol

NMP N-methyl pyrrolidinone

TEA triethylamine

TFA trifluoroacetic acid

THF tetrahydrofuran

LDA lithium diisopropylamine

LHMDS Lithium bis(trimethylsilyl)amide

TBAF tetrabutylammonium fluoride

TLC thin layer chromatography

In general, preparation of the novel amides was completed in four synthetic operations. They are highlighted in Schemes 1, 2, and 3. Methyl 5-iodosalicylate (2, TCI) was subjected to Mitsunobo conditions (triphenyl phosphine-diisopropylazodicarboxylate in toluene) in the presence of a carbinol. The aryl iodides bearing a pendant ether were then converted to biphenyls under palladium catalysis. Parent biphenyl acids resulted in minor amounts from the palladium catalysis conditions and were also generated under standard saponification conditions. Amides were prepared using two different reagents: Carbonyl diimidazole or azabenzotriazol-1-yl)uronium salt (Example 2 or 3, respectively) in the presence of the desired amine counterpart.

Example 1

Methyl 5-iodosalicylate (TCI, 4.9 g, 17.5 mmol), cyclopropane carbinol (Aldrich, 1.15 g, 16 mmol) and triphenylphosphine (Aldrich, 5.45 g, 21 mmol) were dissolved in anhydrous toluene (50 mL) and cooled to 0° C. Diisopropyl azodicarboxylate (Aldrich, 4.1 mL, 21 mmol dissolved in 20 mL of toluene) was added dropwise to the solution above over 15 minutes. After stirring at ambient temperature for 3 days, the mixture was diluted with hexane and directly loaded onto a pad of silica. The desired ether (3, 4.63 g, oil) eluted with an ethyl acetate 5-20% gradient in hexanes and displayed spectroscopic properties consistent with the desired material.

Ether 3 (3.0 g, 9.0 mmol), 4-methoxy-2-methylphenyl boronic acid (Combi-Blocks, 1.65 g, 9.9 mmol), cesium carbonate (Aldrich, 7.3 g, 22.5 mmol), ethanol (5 mL), water (25 mL) and toluene (70 mL) were vacuum purged with nitrogen while heating. Tetrakis(triphenylphosphine) palladium (Strem, 1.04 g, 0.9 mmol) was added and the mixture was heated to reflux for 16 hours with vigorous stirring. Upon cooling to ambient temperature, the phases were separated with the aqueous layer being extracted with ethyl acetate. The combined organic layers were stored over anhydrous sodium sulfate. Upon removal of the volatiles, the desired biphenyl (5, 2.23 g, oil) was isolated by silica gel chromatography (eluant 5-60% ethyl acetate-hexanes) and displayed spectroscopic properties consistent with the proposed structure.

According to Example 1 (substituting benzyl alcohol for cyclopropane carbinol in step 1 then substituting 2-methoxyphenyl boronic acid for 4-methoxy-2-methylphenyl boronic acid in step 2) and the saponification of example 2, 4-benzyloxy-2′-methoxy-biphenyl-3-carboxylic acid (820 mg, 1.77 mol) was prepared.

Example 2

Ester 6 (1.6 g, 4.1 mmol) was dissolved in tetrahydrofuran (60 mL) and methanol (5 mL). The solution was plunged into an ice-bath and treated with lithium hydroxide [(400 mg, ca. 10 mmol) dissolved in water (20 mL)] and stirred at ambient temperature overnight. The volatiles were removed from the mixture and the residue was partitioned between water (50 mL) and ethyl ether (2×30 mL). The aqueous layer was quenched with 10% aqueous acetic acid and extracted with ethyl acetate (3×60 mL) and then stored over anhydrous sodium sulfate. The desired acid was obtained (7, 1.4 g, mp 125-126° C., MS m/z for parent ion M⁻¹ 377) following filtration and removal of the volatiles and it displayed spectroscopic properties consistent to the proposed structure. The acid (255 mg, 0.67 mmol) was dissolved in N-methyl-2-pyrrolidinone (4 mL) and treated with carbonyl diimidazole (108 mg, 0.67 mmol, added in one portion). The solution was stirred vigorously at ambient temperature for 10 minutes. Aminomethyl cyclopropane (0.12 mL, 1.4 mmol) was added rapidly and the resulting golden solution was stirred overnight. The mixture was partitioned between water (20 mL) and heaxane:ethyl acetate (1: 1, 4×25 mL), washed with fresh water, brine, and stored over anhydrous sodium sulfate. The desired amide (8, 185 mg, mp 115.6-116.5° C., MS m/z for parent ion M⁺¹ 432) was isolated by silica gel chromatography (eluant: 10-80% ethyl acetate hexane) with spectroscopic properties consistent to the indicated structure.

According to example 1 (substituting benzyl alcohol for cyclopropane carbinol in step 1 then substituting 2-methoxyphenyl boronic acid for 4-methoxy-2-methylphenyl boronic acid in step 2) and the saponification of example 2, 4-benzyloxy-2′-methoxy-biphenyl-3-carboxylic acid (9, 820 mg, 1.77 mol) was prepared.

The acid 9 (255 mg, 0.55 mmol) was dissolved in N-methyl-2-pyrrolidinone (5 mL) and treated with carbonyl diimidazole (90 mg, 0.55 mmol, added in one portion). The solution was stirred vigorously at ambient temperature for 10 minutes. Aminomethyl cyclopropane (0.12 mL, 1.4 mmol) was added rapidly and the resulting golden solution was stirred overnight. The mixture was partitioned between water (20 mL) and heaxane:ethyl acetate (1: 1, 4×25 mL), washed with fresh water, brine, and stored over anhydrous sodium sulfate. The desired amide (10, 86 mg, oil, MS m/z for parent ion M⁺¹ 388) was isolated by silica gel chromatography (eluant: 10-80% ethyl acetate hexane) with spectroscopic properties consistent to the indicated structure.

Example 3

Ester 5 (2.23 g, 6.8 mmol) was dissolved in tetrahydrofuran (60 mL) and methanol (5 mL). The solution was plunged into an ice-bath and treated with lithium hydroxide [(860 mg, ca. 20 mmol) previously dissolved in water (20 mL)] and stirred at ambient temperature overnight. The volatiles were removed from the mixture and the residue was partitioned between water (50 mL) and ethyl ether (2×30 mL). The aqueous layer was quenched with 10% aqueous acetic acid and extracted with ethyl acetate (3×60 mL) and then stored over anhydrous sodium sulfate. The desired acid was obtained (11, 1.66 g, mp 139-140.5° C., MS m/z for parent ion M⁺¹ 313) following filtration and removal of the volatiles and it displayed spectroscopic properties consistent to the proposed structure. The acid (314 mg, 1.0 mmol) was dissolved in N-methyl-2-pyrrolidinone (4 mL) and treated with O-(7-azabenzotriazol-1-yl)uronium hexafluorophosphate (4210 mg, 1.1 mmol) under N₂. The solution was immediately treated with triethylamine (0.28 mL, 2.0 mmol) and 1-ethynylcyclohexylamine (0.28 mL, 2.1 mmol) allowed to stir at ambient temperature for 16 hours. It was then partitioned between 0.2 M potassium hydrogen sulfate (15 mL) and hexane:ethyl acetate (1: 1, 3×40 mL). The combined organic layers was washed with fresh water then brine and stored over anhydrous sodium sulfate. The extract was reduced in volume to a residue which was subjected to silica gel chromatography. The desired amide (12, 235 mg, oil, MS m/z for parent ion M⁺¹ 418) displayed spectroscopic properties consistent with the proposed structure.

Amide 13 (155 mg, oil, MS m/z for parent ion M⁺¹ 434) was prepared according to example 3 by replacing 1-ethynylcyclohexylamine with 2-fluoro-β-phenethylamine.

Formulations

Pharmaceutical preparations for delivery by various routes are formulated as shown in the following Tables. “Active ingredient” or “Active compound” as used in the Tables means one or more of the Compounds of Formula I.

Composition for Oral Administration Ingredient % wt./wt. Active ingredient 20.0% Lactose 79.5% Magnesium stearate 0.5%

The ingredients are mixed and dispensed into capsules containing about 100 mg each; one capsule would approximate a total daily dosage.

Composition for Oral Administration Ingredient % wt./wt. Active ingredient 20.0% Magnesium stearate 0.5% Crosscarmellose sodium 2.0% Lactose 76.5% PVP (polyvinylpyrrolidine) 1.0%

The ingredients are combined and granulated using a solvent such as methanol. The formulation is then dried and formed into tablets (containing about 20 mg of active compound) with an appropriate tablet machine.

Composition for Oral Administration Ingredient Amount Active compound 1.0 g Fumaric acid 0.5 g Sodium chloride 2.0 g Methyl paraben 0.15 g Propyl paraben 0.05 g Granulated sugar 25.5 g Sorbitol (70% solution) 12.85 g Veegum K (Vanderbilt Co.) 1.0 g Flavoring 0.035 ml Colorings 0.5 mg Distilled water q.s. to 100 ml

The ingredients are mixed to form a suspension for oral administration.

Parenteral Formulation Ingredient %wt./wt. Active ingredient 0.25 g Sodium Chloride qs to make isotonic Water for injection 100 ml

The active ingredient is dissolved in a portion of the water for injection. A sufficient quantity of sodium chloride is then added with stirring to make the solution isotonic. The solution is made up to weight with the remainder of the water for injection, filtered through a 0.2 micron membrane filter and packaged under sterile conditions.

Suppository Formulation Ingredient % wt./wt. Active ingredient 1.0% Polyethylene glycol 1000 74.5% Polyethylene glycol 4000 24.5%

The ingredients are melted together and mixed on a steam bath, and poured into molds containing 2.5 g total weight.

Topical Formulation Ingredients grams Active compound 0.2-2 Span 60 2 Tween 60 2 Mineral oil 5 Petrolatum 10 Methyl paraben 0.15 Propyl paraben 0.05 BHA (butylated hydroxy anisole) 0.01 Water q.s. 100

All of the ingredients, except water, are combined and heated to about 60° C. with stirring. A sufficient quantity of water at about 60° C. is then added with vigorous stirring to emulsify the ingredients, and water then added q.s. about 100 g.

Nasal Spray Formulations

Several aqueous suspensions containing from about 0.025-0.5 percent active compound are prepared as nasal spray formulations. The formulations optionally contain inactive ingredients such as, for example, microcrystalline cellulose, sodium carboxymethylcellulose, dextrose, and the like. Hydrochloric acid may be added to adjust pH. The nasal spray formulations may be delivered via a nasal spray metered pump typically delivering about 50-100 microliters of formulation per actuation. A typical dosing schedule is 2-4 sprays every 4-12 hours.

Example 4 Nicotinic alpha 7 Modulation Assay Cell Cultures

Cell Culture Growth Media: F10 medium (Invitrogen), 2.5% Fetal Bovine Serum (FBS, Summit Biotechnology); 15% heat inactivated donor Horse Serum (Invitrogen), 250 μg/ml Hygromycin B (Invitrogen); and 100 nM Methyllicaconite (MLA, Sigma) are added to each new culture by 50-fold dilution of stock solution prepared in H₂O at 51 μM.

GH₄C₁ cells (rat pituitary-derived cell line) stably expressing human nicotinic alpha7 WT receptor (RPA clone #34.7) are cultivated in cell culture growth media (described above) at 37 C in a humidified atmosphere containing 4% CO₂. Fresh cell stock cultures are initiated with cells at 0.1-0.2×10⁶/ml, 50 ml media per T225 flask and are grown for 2 or 3 days prior to use in FLIPR assay. Cells harvested two days after intiation of stock flask typically yields ˜25×10⁶/T225 flask and 3 days after intiation of stock flask typically yields ˜40'10⁶/T225 flask.

One day prior to assay, cells are placed in in fresh cell culture growth media supplemented with 100 nM fresh MLA. To accomplish media change, suspension cells of the culture are removed and 45 ml fresh cell culture growth media (containing 100 nM fresh MLA) is immediately added to the stock flask as large numbers of cells remain adherent to the surface. The cells in suspension are then collected by centrifugation, resuspended in 5 ml fresh cell culture growth media and returned to the original culture flask.

Buffer Solutions

Buffer solutions used in the assay are HBSS FLIPR buffer (Invitrogen), 2 mM CaCl₂ (Sigma), 10 mM HEPES (Invitrogen), 2.5 mM Probenecid (Sigma), and 0.1% BSA (Sigma)

FLIPR Assay

The alpha 7 nAChR assay is a cell-based functional readout designed to determine the effect of test compounds to either directly activate nicotinic receptor channels and/or to modulate activation by the native agonist acetylcholine (ACh, Sigma).

On day one of the assay, attached cells are lifted using 1×-concentration Versene (Gibco, Cat-No. 15040), combined with cells in suspension, and collected by centrifugation (5 min, 162×g). The cell pellet is resuspended in FLIPR buffer at 0.5×10⁶/ml and cells dispensed into sample wells of a 96-well poly-d-lysine coated black/clear plate (Becton Dickinson) at 0.5×10⁵ cells per well. Sample wells are then supplemented with FLUO-3AM dye (TefLabs, stock solution prepared at 2.5 mM in anhydrous DMSO containing 10% Pluronic acid) in FLIPR buffer at 1 μM final assay concentration (FAC). Dye loading of cells occurs by incubation of plates for one hour at 37 C in a humidified atmosphere containing 4% CO₂. To remove extracellular dye, FLIPR plates are washed using a Biotek EL405 plate washer leaving a residual volume of 0.1 ml FLIPR buffer per sample well.

Assay of test compound effect on activation of the alpha7 nicotinic receptor channel is done by measurement of cytosolic [Ca²⁺] elevation as reported by increased FLUO-3 fluorescence using a two addition experimental design and FLIPR™ (Molecular Devices). Following a 30 second baseline recording, test compounds are added online (dilution scheme below) and cell response is recorded for an additional 5 minutes. After a second addition of ACh (30 μM, FAC), plates are read for an additional 4 minutes.

Test Compound Preparation

Multiple concentrations of test compounds are examined in parallel on each 96 well assay plate. In order to achieve 100 μM (1.00E−4 M) for the highest FAC of test compound, 24 μl of 10 mM test compound stock solution (100% DMSO) is added directly to 576 μl of FLIPR buffer (i.e. highest [test compound]=0.4 mM=4-fold FAC). Starting with the 0.4 mM test compound sample, test compounds are then diluted serially in FLIPR buffer (using Biomek 2000) resulting in the following test compound FACs: vehicle, 1.00E−4 M, 3.16E−5, 1.00E−5 M, 3.16E−6, 1.00E−6 M, 3.16E−7, 1.00E−7 M. Maximum FAC for DMSO=1% in the sample wells exposed to the the highest FAC of test compound of 100 μM. Negative controls were made by vehicle addition, followed by ACh addition. Positive controls were made by 1 μM PNU-120596 addition, followed by ACh addition.

Compound Activity

Values for IC₅₀/EC₅₀, intrinsic agonist activity and positive allosteric modulation for alpha 7 nAChR were determined using ACTIVITYBASE™ data analysis software. For dose-response data, either the fitted mid-point of the curve (inflection) or the point at which the curve crosses a threshold activity value (typically 50% of control) may be used to determine IC₅₀/EC₅₀.

Using the above assay, the compounds of the invention were determined to be positive allosteric modulators for alpha 7 nAChR. For example, the compound 4-cyclopropylmethoxy-4′-methoxy-2′-methyl-biphenyl-3-carboxylic acid (1-ethynyl-cyclohexyl)-amide showed showed an EC₅₀ of 220 nM, and positive allosteric modulation of 255%.

Example 5 Formalin Pain Assay

Male Sprague Dawley rats (180-220 g) are placed in individual Plexiglas cylinders and allowed to acclimate to the testing environment for 30 min. Vehicle, drug or positive control (morphine 2 mg/kg) is administered subcutaneously at 5 ml/kg. 15 min post dosing, formalin (5% in 50 μl) is injected into plantar surface of the right hind paw using a 26-gauge needle. Rats are immediately put back to the observation chamber. Mirrors placed around the chamber allow unhindered observation of the formalin-injected paw. The duration of nociphensive behavior of each animal is recorded by a blinded observer using an automated behavioral timer. Hindpaw licking and shaking/lifting are recorded separately in 5 min bin, for a total of 60 min. The sum of time spent licking or shaking in seconds from time 0 to 5 min is considered the early phase, whereas the late phase is taken as the sum of seconds spent licking or shaking from 15 to 40 min. A plasma sample is collected.

Example 6 Cognition Enhancement

The cognition-enhancing properties of compounds of the invention may be in a model of animal cognition: the novel object recognition task model. 4-Month-old male Wistar rats (Charles River, The Netherlands) were used. Compounds were prepared daily and dissolved in physiological saline and tested at three doses. Administration was always given i.p. (injection volume 1 ml/kg) 60 minutes before T1. Scopolamine hydrobromide was injected 30 minutes after compound injection. Two equal testing groups were made of 24 rats and were tested by two experimenters. The testing order of doses was determined randomly. The experiments were performed using a double blind protocol. All rats were treated once with each dose condition. The object recognition test was performed as described by Ennaceur, A., Delacour, J., 1988, A new one-trial test for neurobiological studies of memory in rats. 1: Behavioral data. Behav. Brain Res. 31, 47-59.

While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto. 

1. A compound of Formula I:

wherein: Q¹ is [CH₂]_(q); q is 0, 1, or 2; Q² is [CH₂]_(r); r is 1 or 2; R¹ is R^(1′) or R^(1″); R^(1′) is phenyl optionally substituted with halogen; R^(1″) is cycloalkyl optionally substituted with alkynyl; R² is R^(2′) or R^(2″); R^(2′) is phenyl optionally substituted with lower alkoxy; R^(2″) is cycloalkyl; R³ is lower alkoxy or lower alkyl; and n is 0, 1, or
 2. 2. The compound of claim 1, wherein Q¹ is methylene and R¹ is cyclopropyl.
 3. The compound of claim 2, wherein Q² is methylene and R² is phenyl.
 4. The compound of claim 2, wherein Q² is methylene and R² is 4-methoxy-phenyl.
 5. The compound of claim 1, wherein q is 0 and R¹ is cyclopentyl.
 6. The compound of claim 5, wherein Q² is ethylene and R² is phenyl.
 7. The compound of claim 6, wherein n is 2 and each R³ is independently methyl or methoxy.
 8. The compound of claim 1, wherein Q¹ is ethylene and R¹ is 2-fluoro-phenyl.
 9. The compound of claim 8, wherein Q² is methylene and R² is R^(2′).
 10. The compound of claim 9, wherein n is 1 and R³ is methoxy.
 11. The compound of claim 9, wherein n is 2 and each R³ is independently methyl or methoxy.
 12. The compound of claim 1, wherein q is 0 and R¹ is R^(1″).
 13. The compound of claim 12, wherein R^(1″) is 1-ethynl-cyclohexyl and Q² is methylene and R² is cyclopropyl.
 14. The compound of claim 13, wherein n is 2 and each R³ is independently methyl or methoxy.
 15. The compound of claim 1 selected from the group consisting of: 4-Benzyloxy-2′-methoxy-biphenyl-3-carboxylic acid cyclopropylmethyl-amide; 4-Benzyloxy-2′-methoxy-biphenyl-3-carboxylic acid [2-(2-fluoro-phenyl)-ethyl]-amide; 4′-Methoxy-2′-methyl-4-phenethyloxy-biphenyl-3-carboxylic acid cyclopentylamide; 4′-Methoxy-2′-methyl-4-phenethyloxy-biphenyl-3-carboxylic acid [2-(2-fluoro-phenyl)-ethyl]-amide; 4′-Methoxy-4-(4-methoxy-benzyloxy)-2′-methyl-biphenyl-3-carboxylic acid cyclopropylmethyl-amide; 4-Cyclopropylmethoxy-4′-methoxy-2′-methyl-biphenyl-3-carboxylic acid (1-ethynyl-cyclohexyl)-amide; and 4-Cyclopropylmethoxy-4′-methoxy-2′-methyl-biphenyl-3-carboxylic acid [2-(2-fluoro-phenyl)-ethyl]-amide.
 16. A method of enhancing cognition in a subject in need thereof, said method comprising administering to said subject an effective amount of a compound of claim
 1. 17. The method of claim 16, wherein said subject has Alzheimer's disease.
 18. A pharmaceutical composition comprising the compound of claim 1 in admixture with at least one pharmaceutically acceptable carrier, diluent or excipient. 